Author Topic: 1987 K100 cafe or something build  (Read 50423 times)

Offline Revrdmark

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1987 K100 cafe or something build
« on: July 26, 2016, 09:40:45 PM »
    So I picked up two late 80's K100's cheap. One had a bad engine but clean title,  the second had a good engine and tranny but a salvage title. (From what I understand the salvage title comes from the bike that was originally an LT was laid down and the luggage and fairings were destroyed so insurance totaled it, but the engine and frame were untouched. So the previous owner bought  some ratty RS fairings for it and rode it a couple more years.







So the first job is to strip the fairings down and get to the bare frame and engine on each bike and do an engine swap.


(BTW all the fairings and luggage are for sale except the gold top case it's already claimed. If you are interested in anything let me know. )

 So the engine swap is not that difficult. Just undo 5 bolts and lift the front wheel forks and frame off the engine and shaft drive. The hardest thing was getting the cables and wires disconnected to pull the frame off the engine.





    So now that the engine is swapped I need to check my wiring diagram in my manual and see if I can  get rid go that big dash and replace it with a couple dials  (speedo and tach). Also need to decide if I'll do straight drag bar, clubman bars or clip on's  I'll  post more as I progress.
  • Spokane WA
  • 87 K100

Offline iiXioM

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  • Posts: 52
Re: 1987 K100 cafe or something build
« Reply #1 on: July 27, 2016, 09:50:20 AM »
Hey man good luck on your project! Working on these things is fun and easier than anticipated once you get your hands in.

Question about the 'ratty fairings' on the RS. What do you mean about ratty? lol. I'm restoring an 85RT that had no plastics (check my thread) to something, and are interested in the RS fairings. Send me a message when you're free and maybe we can make a deal or something.
  • New Orleans, LA
  • 1985 BMW K100RT

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #2 on: July 27, 2016, 10:35:36 AM »
Hey man good luck on your project! Working on these things is fun and easier than anticipated once you get your hands in.

Question about the 'ratty fairings' on the RS. What do you mean about ratty? lol. I'm restoring an 85RT that had no plastics (check my thread) to something, and are interested in the RS fairings. Send me a message when you're free and maybe we can make a deal or something.

They are actually in very good shape minus one of the holes was split  on the right side bottom where the rubber inside piece attached. (It is a 20 Minute fiberglass repair)  By ratty I mean that they have some rick chips and they have a home made paint job with a blue/black color, no idea if its factory match or not. the windshield has a  blemish as well. It had a pair of black luggage as well, they need some fiberglass repair as well. The second picture at the top is the bike so you can get the general idea. I'll get you some pictures and send you a PM tonight.

Im finding that the systems and engine function more like a car than a motorcycle so i'm having to  just adjust my way of thinking a little to get my head around charging systems and  wiring and fuel injection etc...  I'm not looking forward to   figuring out the wiring for the  instrument cluster replacement. I'll have to do some digging to see if someone as already recorded their work in rewiring  new gauges.
  • Spokane WA
  • 87 K100

Offline Revrdmark

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1987 K100 cafe or something build
« Reply #3 on: July 30, 2016, 11:30:17 PM »
So I have the engine swapped and all the wires hooked back up and WALLA! It runs!!!

I've been looking at all the threads about switching instrument cluster and it looks like a PITA so I think I have decided to keep the stock cluster and fab a new bracket to lower it a bit and tuck it inside a bullet fairing for a kinda Ducati GT 1000 look. We'll see I might change my mind before next spring.

I'd like to replace the handlebar controls but not sure if that would require much rewiring. I'm not a fan of the big bulky controls and really don't like the separate turn indicator switches on both sides. My concern is the clutch switch and the break reservoir pressure with an aftermarket one. Has anyone replaced them and have any advise?


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  • Spokane WA
  • 87 K100

Offline TrueAce

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Re: 1987 K100 cafe or something build
« Reply #4 on: July 31, 2016, 12:50:12 AM »
Well, the short answer for you on changing any of the stock bar controls is that it can be complicated. Just take a look at the wiring diagram for your bike, if you aren't frowning at that, remove the seat and take and look at the wiring loom...........should turn away from cosmetic control issues, and just do all the maintenance no doubt neglected.
  • Florida
  • '85 K100GS, '85 K100RSSC,', '94 K1100RS,'10 S1000rr,'14 Ural Sidecar, '15 R Nine T

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #5 on: August 01, 2016, 02:16:53 AM »
Well the throttle controls side would also need a throttle cable since the throttle tube has that weird gear chain cable combo. But the start button, break light switch, and kill switch I could just splice in. The left side controls are a bit more complicated with the clutch engage switch, chock lever.

I'm also  exploring aftermarket exhaust the mid pipe is a bit of a challenge with the 4-1  running laterally  rather than horizontally. Would any 1000cc exhaust be an acceptable replacement. I was wondering about back pressure and fuel delivery volume in the injection system.


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  • Spokane WA
  • 87 K100

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #6 on: August 08, 2016, 12:26:40 AM »
So i'm going to bite the bullet and do the control swap. i got a little work done while i am waiting for parts. Since my local shop had a single cable pull throttle tube mechanism and some handle bars i liked I purchased them and started the next stage of the project.  Since the cables were so long for the "elk horn" bars that were on the bike, i trimmed about 4" off the throttle cable and  soldered a new end on it to fit the hole in the throttle tube cam. i made a little home made melting pot and melted the solder and dipped the end in it to fasten it. It worked surprisingly well!




Bolted the tube and mechanism to the bars, it trimmed up the look quite a bit. I'm pretty happy with it.


I have the left and right controls from an '02 Kawaski ZZR 1200 coming in the mail that are considerably smaller than the BMW  controls. They should splice into the wires fairly simply (famous last words right!)

So at this point i have one running bike that i've created out of two with a clean title. The '87 frame has a '89 engine and drive in it now.

I'm waiting for the bullet fairing i bought to arrive and i'll see if i am going to keep the instrument cluster and avoid the head ache of  the wiring for a new one. I have a new brake master cylinder coming and clutch pull and lever on the way with the appropriate switches and I'll go from there once they arrive.

This is how she looks so far!



My biggest challenge has been work space! I live in a house built in 1910 and te garage was built for a car the size of a Model T so having a project bike, a parts bike a Speed Triple and  Buell Ulysses in one garage makes for some creative positioning to get to things! I am so jealous of you guys that post pictures of big shops with big ol' work benches to work at!
  • Spokane WA
  • 87 K100

Offline TimTyler

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Re: 1987 K100 cafe or something build
« Reply #7 on: August 08, 2016, 01:05:38 AM »
My biggest challenge has been work space! I live in a house built in 1910 and te garage was built for a car the size of a Model T

Consider yourself lucky. I don't have a garage.  :yow

Offline TrueAce

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Re: 1987 K100 cafe or something build
« Reply #8 on: August 08, 2016, 09:39:55 AM »
The new bars look good........what brand? And 22mms?
  • Florida
  • '85 K100GS, '85 K100RSSC,', '94 K1100RS,'10 S1000rr,'14 Ural Sidecar, '15 R Nine T

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #9 on: August 08, 2016, 10:50:50 AM »
The new bars look good........what brand? And 22mms?

They are Track Side bars. 7/8" since I was replacing all the controls there were more options in that size. I like a little rise to them but we will see how high I have to mount the fairing for clearance. Straight drag bars would give me more room to mount the fairing lower and  stream line the look more. I may switch them out yet.


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  • Spokane WA
  • 87 K100

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #10 on: August 10, 2016, 09:24:15 PM »
I'm looking ahead to projects down the road. I'd like to switch out the exhaust at some point. I'm interested in the 4" super trap muffler ( I had one on a 87 Honda interceptor that I learned to ride on when I was 20 years old. ) Anyway, anyone have experience with them? Also wondering if anyone has a link to a 4-1 piece that would get me to the 2" opening on the super trapp or am I going to have to see if my muffler shop can fab one ?


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  • Spokane WA
  • 87 K100

Offline Laitch

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Re: 1987 K100 cafe or something build
« Reply #11 on: August 10, 2016, 09:49:03 PM »
Also wondering if anyone has a link to a 4-1 piece that would get me to the 2" opening on the super trapp or am I going to have to see if my muffler shop can fab one ?
Like this? It might need a reducer. Some heating and ventilating outfits can fabricate that stuff, too.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
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Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #12 on: August 12, 2016, 01:15:43 AM »
For the record let me just say ... I hate wiring motorcycles!


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  • Spokane WA
  • 87 K100

Offline Revrdmark

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1987 K100 cafe or something build
« Reply #13 on: August 13, 2016, 01:02:23 AM »
Hooray!!! I got the left controls  from an '02 ZZR 1200 wired in after a lot of trial and error. To be honest I'm not sure  how I did it just going through one function button and circuit at a time till they all worked. Tomorrow I'll tackle the right side start and kill switch






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  • Spokane WA
  • 87 K100

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #14 on: August 13, 2016, 11:54:45 PM »
Ok the ZX10 starter button and kill switch are installed and working. Only one problem ... When I flip the kill switch from dead to run the brake light comes on. I have no idea why.  The original lever and switch are still connected. I'm wondering if they might share a ground or something with the ignition button or something. If I can't track down why I may just  run the break light separate from the original loom.


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  • Spokane WA
  • 87 K100

Offline Shiny

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Re: 1987 K100 cafe or something build
« Reply #15 on: August 14, 2016, 09:00:51 PM »
Great work! The bmw turn signals are idiosyncratic to say the least. It'd be great if you could try to take a pic of the wiring for documentation.
  • Northern Virginia
  • BMW K75T

Offline NickHeijman

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Re: 1987 K100 cafe or something build
« Reply #16 on: August 15, 2016, 08:39:47 AM »
Woow good job on the controls.

Could you drop some pictures and some documentery, if possible. It would be helpfull for all other.
Changing the controls will be one of the steps ill be taking on my CF.

Cheers,
Nick
  • Breda
  • BMW K75S

Offline Revrdmark

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1987 K100 cafe or something build
« Reply #17 on: August 15, 2016, 10:26:24 AM »
I'll get a write up and some pics up soon. It's VBS week so Work is busy this week so I'll try and get something up in one of the evenings.


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  • Spokane WA
  • 87 K100

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #18 on: August 15, 2016, 07:31:07 PM »
So here is a little write up for replacing the handle bar controls on a 1987 BMW K100,

I initially removed the handlebars because the K100 was originally an LT model with very high rise bars and I wanted something sleeker. 7/8” bars were the most easily accessible but that would mean replacing the throttle tube, clutch and break levers and the buttons and controls on the bars. Secondly I did not like the big box of buttons on the stock controls.  Finally I wanted to move the turn indicator switch to a toggle switch on the left hand, rather than one on each side with the turn off on the right.

Originally, I had planned on using some Chinese controls that I have used on some other cafι racer projects I have built, but the left control also has a cable that the choke works off of and none of the aftermarket controls had a lever to engage the choke. So I just began looking for left hand handlebar controls on eBay. Nothing after-market filled the bill of a high/low beam headlight switch, toggle switch for left and right turn signals, horn and a built in lever for the choke. I came across a used 2002 Kawasaki ZZR 1200 left hand control that has a choke lever built in, the high/low beam switch and the turn signal toggle switch. The same seller had a 2010 ZX10 right side control with kill and starter switch, so I combined shipping and ordered them both. They matched up well, were smaller than the stock ones, and look in great shape .(If you are wanting to do a similar switch I don’t have the original Kawasaki Part #’s but a simple OEM part search at a place like Bike Bandit will get you the information. Or look on eBay like me. I got the units for each under $15)

The Left controls (From the ZZR1200) were a little challenging to figure out until i figured out that the  turn signal  and the horn button shared a ground on the stock switch.  Plus I had to bring the wire for the right side turn signal over from the  right side stock controls and ground the signal stop switch on the right as well. The nice thing about buying two bikes to make one complete  running bike is that you have spare parts, so I was willing to  basically cut the wires, open up the  stock controls and  take it apart to see what  wire connected to what switch along with my Hayes repair manual wire diagram. If I screwed it up too bad I could always grab the switches from the donor bike and put everything back by reconnecting the  wires.

So here is  the way I wired up the turn signal toggle, High/Low beam toggle and horn button on left hand control.



Turn switch toggle & Horn:
             From ZZR control --------------- to ---------------Stock K100 wire harness
                1. Orange + Blk/Grey (from Horn button).... Brown
                2. Blk/Yellow………………………………………..…. Brown/Yellow
                3. Green…………………………………………………… Blue/Red
                4. Grey …………………….………………………….…. Blue/Yellow (from the turn signal
                                                                                              button on right control)



Hi/Low Beam switch:
            From ZZR control --------------- to ---------------Stock K100 wire harness
                  1. Red/Yellow …………………………………………. Yellow
                  2. Blue/Yellow ………………………………………… Yellow/White
                  3. Red ……………………………………………………… White
                                                                               Unused Blue/Green - Extra wire for parking light.



Here is how I wired the kill switch and starter button on the right side control. (The ZX10 control has an extra switch that is unused at this point so there will be two extra wires that are not connected when you are done.  Also when I wired the ZX10 control up and turned the kill switch to run the break light turns on.  I am still tracking that issue down. If I can not figure out the cause I will just runt the break light switch as a separate system from the rest of the wiring harness and snip the original break light wire. At this point I still have the original brake lever connected so it may be an issue with the stock brake switch and not my wiring of controls but we will see once its all buttoned up.)



                 ZX10 Control ---------------------- To ------------------ Stock BMW K100 Wire harness
                         1. From 1 side of Ignition button Blk/Red ………… Blk/Yellow
                         2. From 1 side of Ignition button Blk/Red ………… Blk/Green
                         3. From Kill Switch , Yellow/Red ………………………. Green
                         4. From Kill Switch, Red ……………………………………. Green/Yellow
                         5.                                          Brown to Ground (-)
                         6.                                     Brown White to Ground (-)

  • Spokane WA
  • 87 K100

Offline Revrdmark

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1987 K100 cafe or something build
« Reply #19 on: August 20, 2016, 08:05:45 PM »
So a little more work today. I got a little bullet fairing a few weeks ago and was trying to figure out how to mount it. I originally thought I'd modify the faring stay and mount it to that. But when I mocked it up it had to be so far forward and so high to clear the new bars the lines looked terrible. So I thought I would mount it on some left over screw holes on the triple tree and fabricate a bracket of some kind.  So I used some flat steel and a vice  to bend up a little mount and welded it with my arch welder. I'm still learning welding and I kinda suck at it but black paint covers a multitude of sins :-)



I used some left over angle iron to make the top bracket. Originally I used a torch to heat up some old rebar and try and get them bent at correct angles and lengths on each side and then weld them to the angle iron. With my little torch, grinder, hammer and bench vise as my only metal working tools I couldn't get the angles and length correct and my welds sucked so I went with plan "B"

I took some threaded rod and ran it through one of the windshield bolt holes, put a fender washer on the inside and a nut on the outside. I used u-bolt to lock it down to the angle iron and it was pretty sturdy and looks much cleaner than my booger welds. Plus I can turn the bolts and get the lengths as exactly centered as I like.



It's starting to look like a motorcycle again rather than a bunch of pipes bolted to an engine.


Next will be fitting light in that fairing and a seat pan and chopping the rear frame and reinforcing to fit.



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  • Spokane WA
  • 87 K100

Offline TrueAce

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Re: 1987 K100 cafe or something build
« Reply #20 on: August 20, 2016, 08:08:06 PM »
Clever! Keep going.....good post!
  • Florida
  • '85 K100GS, '85 K100RSSC,', '94 K1100RS,'10 S1000rr,'14 Ural Sidecar, '15 R Nine T

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #21 on: August 22, 2016, 11:03:24 PM »
So had the day off today  so i finished up connecting wires and tucking them away. 

I'm not sure the story but the the bike that donated the engine and drive train started life as a LT model with ABS, but no brain t make it work. I took the conventional brakes off the donor bike and installed them on the keeper bike and removed the calipers with the  sensors on them and the two solenoids from the keeper bike. (If you are interested in them they are for sale.) I took the  wiring harness for the ABS out and cleaned things up in general.

I'll be installing a new koso speedometer when it comes in a big brown truck. Am I correct in  the fact that the speedo drive on the rear wheel is not a typical reed sensor and wont directly connect to the new speedo w/o  modification?

I'll be relocating the ECU under the seat and moving the battery to the tail section but  I'm running out of room on the handlebars and might  look for a new place to mount my key ignition switch. Anyone moved their  key to a new location and have any suggestions or advise?
  • Spokane WA
  • 87 K100

Offline pablooo

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Re: 1987 K100 cafe or something build
« Reply #22 on: August 23, 2016, 12:04:04 AM »
As for the ignition relocation, I've seen them in the airbox such as what a fellow motobricker did here http://www.motobrick.com/index.php?topic=3605.0 or what I did, as i've seen some others on here do as well was use two wormgear clamps (one to the ignition and one on the frame intertwined with each other) to the frame on the side or wherever you'd like.
  • Austin, Tx
  • BMW K100, FZ-07

Offline Revrdmark

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Re: 1987 K100 cafe or something build
« Reply #23 on: August 23, 2016, 01:54:30 AM »
That air box mount looks very cool. I was thinking of maybe mounting the key cylinder on top of the coil covers where there is a power port at the moment with either a plastic or sheet metal bracket


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  • Spokane WA
  • 87 K100

Offline TrueAce

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Re: 1987 K100 cafe or something build
« Reply #24 on: August 23, 2016, 11:36:16 AM »
One switch is ignition, the other for lights so no drain during starting, the brass started button gets it going. You put the bike in neutral before and after using the left-side starter switch.
  • Florida
  • '85 K100GS, '85 K100RSSC,', '94 K1100RS,'10 S1000rr,'14 Ural Sidecar, '15 R Nine T

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